F16.99 — Hallucinogen use, unspecified with unspecified hallucinogen-induced disorder

BillableUnspecified

Is F16.99 billable?

Yes, but F16.99 is an unspecified code. F16.99 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, F16.99 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting F16.99 — the more specific alternatives are listed below.

More specific alternatives

F16.99 at a glance

Code	F16.99
Description	Hallucinogen use, unspecified with unspecified hallucinogen-induced disorder
Billable	Yes
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

Which MS-DRGs does F16.99 group to?

F16.99 sits in MDC 20 and helps define the logic of 4 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

894Alcohol, Drug Abuse or Dependence, Left AMAmedical
895Alcohol, Drug Abuse or Dependence with Rehabilitation Therapymedical
896Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy with MCCmedical
897Alcohol, Drug Abuse or Dependence without Rehabilitation Therapy without MCCmedical

How is F16.99 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to F16.99. They show the wording a clinician may have documented, which often differs from the Tabular description.

Use › hallucinogen NEC › with › unspecified disorder (of)

Excludes1 — never code together — inherited from F16.9

The conditions below can never be reported together with F16.99 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

hallucinogen abuse (F16.1-)
hallucinogen dependence (F16.2-)

Excludes2 — not included here — inherited from Chapter 5

The conditions below are not part of F16.99, but a patient may have both at the same time. When documentation supports it, F16.99 and the excluded code may both be reported.

symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

How long has F16.99 existed?

F16.99 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.